Understanding blood thinners

These medications don't actually "thin" your blood, but they do help prevent dangerous clots.

For many people with cardiovascular disease, drugs that discourage blood clots are potential lifesavers. If a blood clot lodges in an artery or vein, it can choke off the blood supply to the heart, brain, leg, or lung, with possibly dire consequences.

Not all clots are bad, of course. Clots help stanch bleeding if you're injured. The trick with clot-preventing drugs — commonly referred to as blood thinners — is finding just the right balance between helpful and harmful clotting, says cardiologist Dr. Gregory Piazza, associate professor of medicine at Harvard Medical School.